This SPN 3563 FMI 20 document is a Detroit DD Series fault-code procedure for an ambient and inlet manifold pressure difference (low box) across all model years. It compares manifold pressure to barometric pressure to judge the sensor and the charge air system.
Official document details
| Brand | Detroit |
| Model coverage | Detroit DD Series (EPA 2007-Current) |
| System / group | DD Series / DTCs |
| SPN | 3563 |
| FMI | 20 |
| Condition | ambient and inlet manifold pressure difference (low box) |
| Emissions level | all model years |
| Source | Detroit Power Service Literature |
| Pages | 3 |
| File size | 0.3 MB |
| Format | |
| Language | English |
SPN 3563 FMI 20 troubleshooting steps
With the ignition on you compare inlet manifold air pressure to barometric pressure; a reading outside 0.5 psi calls for a new intake manifold pressure/temperature sensor. The same comparison is repeated at idle, and if both pass you perform a Charge Air Cooler inspection and leak test per the vehicle manufacturer literature, then contact the Customer Support Center with the diesel diagnostic tool log file if no fault is found.
- Fault description: ambient and inlet manifold pressure difference (low box)
- Steps 1 to 3 – Compare manifold pressure to barometric, key on
- Steps 4 to 6 – Repeat the comparison at engine idle
- Step 7 – Charge Air Cooler inspection and leak test
- Customer Support Center and log-file escalation
Applicable truck models
This fault code applies to Detroit DD Series diesel engines of all model years using an intake manifold pressure/temperature sensor and a Charge Air Cooler. The leak test follows Original Equipment Manufacturer literature; confirm the sensor part against Detroit resources on the official Detroit Diesel website.
Who needs this SPN 3563 FMI 20 manual
Diesel technicians and workshop owners chasing a boost-pressure mismatch on a Detroit engine use this document to decide between the manifold sensor and a leaking charge air system before escalating to the Customer Support Center.
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